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First notes about NEMOVAR code

Wednesday 7 July 2010, by Tital

The basic experiment is ORCA 1° - 42 levels
Only 3D-VAR FGAT is working for this configuration (See cppkeys_orca_1_42 in namelist )

- SST data are stored as the TYPE obs_surf (surface observations) defined in nemo/modipsl/modeles/NEMO/OPA_SRC/OBS/obs_surf_def.F90.

This type contains meta data concerning the SST data (for instance robs, rmod (model counterpart), ntyp (type of surface product) and a pointer to the observations data (vector). Two different kinds of SST data are available:

  • initial SST data in sstdata
  • quality controlled SST data in sstdatqc (defined in nemovar/inner/obstore.F90)
  • nemovar_innner_drivers.F90: minimisation module z_y: observations, actually -d

- Namelists

  • nemo/scripts/generic/nemovar_namelist.h
  • nemo/scripts/generic/namelist.nemo

- Modules

  • oer : R^py simulator (p=-1, -1/2, 1/2 or 1 only) see oer_rpy_obs_sst. Seems that jp_diag_oer is forced (initialized) to 1 (which corresponds to a diagonal R)

- Control vectors as a total size nsize: have a look at

  • varctl.F90 where the TYPE ctlvec is defined:
    • nctl3d-3d, nctl-2d, nctl-ex can only be changed in SUBROUTINE init_ctlvec
  • control_vector.F90
  • It is organized as follow:
    • first come n3d 3D fields, each one with size nsize3d
    • then follow n2d 2D fields, each one with size nsize2d
    • finally come nex extra parameters with total sizensize3d
  • write_ctlvec -> output

- The observation vector seems to be organised as follow

- Switches:

  • ln_sst is true when gridded SST data are token into account in the assimilation process. It is defined in obshand.F90
  • ln_t3d in situ profile data

- Subroutines of interest:

  • nemovar_inner.F90: main code of the inner_loop
  • simvar (see To Do list and complete)
  • obs_read_sst in modips/modeles/NEMO/OBS

To Do

Study the main code of the inner loop nemovar_inner.F90 See namelist_nemovar dans nemo/scripts/generic Check if sstdatqc contains the innovation Check simvar : operator simulator (H) Check with Anthony that R diag is hard coded (via jp_diag_oer parameter) Check where nemovar.output is located to "tail" it Find the namelist where the cppkey for ORCA and 3D-VAR FGAT is initialised Find ngetsst


SST data are stored in: ec:/ocx/NEMO/FORCING/V2/ORCA1_Z42_v2/oiv2 They are used as a forcing term. "netgetforcing" box in XCDP

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